Katsuo (鰹)



When I think of food in spring/summer, I always think of fresh Katsuo. It is currently in season, so if you live in Japan, you will probably see more Katsuo in the market. 

What is Katsuo?

Katsuo is one of the beloved fish used in Japanese cuisine for at least 8000 years since Jyomon era. It is a medium-sized fish with an average body length of about 50cm and lives in tropical and temperate waters worldwide. The English name of Katsuo is Skipjack tuna or Bonito. 

Why Katsuo has seasons?

Katsuo is a migratory fish, so it changes location between seasons. The majority of Katsuo fished in Japan inhabit the South Pacific Sea during the winter. From April through May, they start to travel toward north along the Pacific coast of mainland Japan. The destination is the Sanriku coast, where warm and cold currents collide, providing an abundant feeding ground. The Katsuo fished during this migratory season is called “Hatsugatsuo (初鰹)” meaning the first Katsuo (first catch) of the season. Hatsugasuo is lean, firm, light, and fresh. 

There is another season of Katsuo

Once Katsuo reaches the Sanriku coast, they stop traveling north and feed in the rich waters during the summer. Then, from September to October, as water temperature drops,  they start traveling back south to mate and spawn. It is considered a second Katsuo season. The Katsuo caught during this time of the year is called “Modori Katsuo (戻り鰹),” meaning returning Katsuo. After feeding all summer, Modori Katsuo has more fat content compared to Hatsugatsuo. As a result, it has a deep, rich, buttery flavor. 

How to eat Katsuo?

Many people enjoy the fresh catch as Sashimi or “Katsuo no tataki,” meaning lightly seared Katsuo. Katsuo no tataki is usually enjoyed with soy sauce-based dipping sauce along with some condiments like ground ginger, garlic, scallion, and/or thinly sliced onions. It is such a refreshing food to enjoy during the rainy season.  So enjoy the first catch of the season while it last!